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. Author manuscript; available in PMC: 2017 Apr 1.
Published in final edited form as: Econ J (London). 2016 Dec 7;126(596):F28–F65. doi: 10.1111/ecoj.12420

Table 5.

Inference Results: Abecedarian Intervention

Variable # C # T Ctr. M. Treat. M. Diff. Ms. Asy. p-val. Naive p-val. Blk. p-val. Per. S.D. Blk. p-val. IPW P. S.D. Bonf. p-val.
(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)
Physical Health in the 30s - Males
Measured weight 9 18 100.6 93.80 6.850 0.242 0.274 0.320 0.320 0.154 0.303 0.462
Measured height 9 18 1.739 1.790 0.050 0.044 0.061 0.083 0.187 0.215 0.215 0.645
BMI 8 18 33.29 29.22 4.075 0.076 0.108 0.141 0.175 0.093 0.204 0.279
Overweight (BMI≥25) 8 18 0.750 0.722 0.028 0.444 0.455 0.391 0.466 0.234 0.234 0.468
Obese (BMI≥30) 8 18 0.625 0.556 0.069 0.376 0.378 0.448 0.448 0.227 0.335 0.454
Diastolic blood pressure 9 19 92.00 78.53 13.47 0.017 0.046 0.075 0.075 0.025 0.025 0.050
Systolic blood pressure 9 19 143.3 125.8 17.54 0.022 0.059 0.057 0.085 0.019 0.031 0.038
Hypertension I 9 19 0.444 0.105 0.339 0.019 0.043 0.063 0.063 0.010 0.018 0.020
Hypertension II 9 19 0.556 0.211 0.345 0.033 0.049 0.061 0.095 0.037 0.037 0.074
Health Insurance at 30 y.o. - Males
Health care coverage 21 27 0.476 0.704 0.228 0.057 0.062 0.080 0.080 0.040 0.040 0.080
Employer-provided/bought 21 27 0.333 0.444 0.296 0.021 0.018 0.034 0.048 0.035 0.055 0.070
Demand for Health Care in the 30s - Males
Hospitalized 9 19 0.556 0.211 0.345 0.033 0.039 0.042 0.042 0.100 0.100 0.200
Scheduled treatment/exam 21 27 0.476 0.222 0.254 0.033 0.040 0.026 0.051 0.043 0.080 0.086
Lifestyles: Diet and Physical Activity at 21 y.o. - Females
Physical activity 28 25 0.071 0.320 0.249 0.010 0.013 0.009 0.009 0.004 0.004 0.008
# Fruit servings 28 25 0.286 0.800 0.514 0.005 0.009 0.002 0.004 0.003 0.006 0.006
Lifestyles: Drinking at 30 y.o. - Females
Not a frequent drinker 28 25 0.857 0.880 0.023 0.405 0.414 0.493 0.586 0.547 0.547 1.000
Alcohol consumption 28 25 3.536 3.180 0.356 0.422 0.430 0.536 0.536 0.516 0.586 1.000
Age of onset < 17 28 25 0.571 0.280 0.291 0.016 0.018 0.023 0.061 0.009 0.023 0.018

Notes: This table presents the inference results for selected outcomes of the Abecedarian Intervention. The columns present the following information: (1) describes the variable of interest; (2) displays the sample size for the control group; (3) displays the sample size for the treatment group; (4) displays the control mean; (5) displays the treatment mean; (6) displays the unconditional difference in means between treatment and control groups (absolute value); (7) displays the asymptotic p-value for the one-sided single hypothesis based on the t-statistic associated with the unconditional difference in means. The remaining columns present permutation p-values based on 30,000 draws. (8) displays the single hypothesis one-sided naive permutation p-value (by naive we mean based on an unconstrained permutation scheme); (9) displays the one-sided single hypothesis constrained permutation p-value based on the t-statistic associated with the difference in means between treatment groups (by constrained permutation we mean that permutations are done within strata defined by the pre-program variables used in the randomization protocol: gender, cohort indicator, number of siblings, high risk index at birth, and mother WAIS full IQ score. More specifically, we simulate the pairwise matching defined in the randomization protocol using these variables and permute the treatment status within matched participants). (10) displays the multiple hypothesis testing (stepdown) p-values associated with (9). The multiple hypothesis testing is applied to blocks of outcomes indicated by horizontal lines. (11) displays the one-sided single hypothesis constrained permutation p-value based on the IPW (Inverse Probability Weighting) t-statistic associated with the difference in means between treatment groups. Probabilities of IPW are estimated using gender- and wave-specific covariates. See Campbell et al. (2014) for details. (12) displays the multiple hypothesis testing (stepdown) p-values associated with (11). The multiple hypothesis testing is applied to block of outcomes indicated by horizontal lines. (13) displays the Bonferroni p-value=m × pIP W, where pIP W is the unadjusted p-value in col. (11) and m is the number of hypotheses to test in the block.

Ctr. or C=Control; Treat. or T=Treatment; M.=Mean; Ms.=Means; Diff.=Difference; Asy.=Asymptotic; Blk.=Block; Per.=Permutation; p-val.=p-value; S.D.=Stepdown; y.o.=years old; IPW=Inverse Probability Weighting; Bonf.=Bonferroni.